Geometrical instruments – Indicator of direction of force traversing natural media – Level or plumb – terrestrial gravitation responsive
Reexamination Certificate
2001-07-03
2003-05-27
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Indicator of direction of force traversing natural media
Level or plumb, terrestrial gravitation responsive
C033S382000, C033SDIG001
Reexamination Certificate
active
06568095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to measuring tools and devices, and more particularly to a small, “torpedo” type spirit level having magnetic means for temporarily securing the level to a ferrometallic structure and further means for adjustably positioning at least one level vial therein. The present magnetic torpedo level is particularly well suited for use in the electrical and plumbing fields, where ferrometallic pipe or EMT (electrical metal tubing) is used and bends to predetermined angles are placed in such pipe or tubing.
2. Description of the Related Art
Small, “torpedo” type spirit levels are popular measuring tools for people working in a number of different technical fields. Such levels are quite suitable for measuring bend angles in pipes and other similar functions, where it is not necessary to establish an absolutely precise horizontal or vertical line (e.g., building wall construction, etc.). Torpedo levels provide additional utility in that they are also easily stored within a relatively small space in a toolbox or the like, and do not require a large amount of storage space in the tool kit of the journeyman worker.
As many such levels are used in measuring the level or angle of pipe runs and EMT lines and the like, various variations of magnetic attachment means for such torpedo levels have been developed in the past. These various magnetic attachment means have fallen short of the magnetic attachment means of the present magnetic torpedo level, in that they have failed to provide sufficient magnetic attraction to hold the level securely in place during pipe and tube bending operations. The various magnetic levels of the prior art also differ from the present invention in various structural aspects, as well.
Another critical point particularly in the electrical and plumbing fields, is the need to bend tubing and pipe to certain predetermined angles in the field. Pipe and tubing is commonly bent to bisect a vertical quadrant, i.e., to form a 45 degree angle between the horizontal and vertical, with that 45 degree angle being further bisected to form a 22.5 degree bend angle in many cases. Yet, most levels contain level vials immovably affixed in place only parallel and perpendicular to the major axis of the level, with only a very few levels including even a 45 degree angle. None of the levels known to the present inventor include a level vial set at a 22.5 degree angle to the major axis of the level, and further, none of those known levels include any means of precisely adjusting the angular position of any of their vials to broaden the utility of the level.
Accordingly, a need will be seen for a magnetic torpedo level including novel magnetic means for temporarily attaching the level to a ferromagnetic structure, to provide a secure grip for the level until it is removed by the user. Moreover, the present magnetic torpedo level includes at least one angularly adjustable level vial therein, allowing the adjustable level vial to be precisely positioned as desired to certain predetermined angles as established by the vial holding fixture or frame within the level.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 1,617,937 issued on Feb. 15, 1927 to George F. Boucher et al., titled “Illuminated Level,” describes a level having a pair of magnets removably installed in depressions in one side thereof. An elevation view in section clearly shows the magnets to be flush with the surface of the level, unlike the present magnetic level. The Boucher et al. level cannot provide a secure grip to a cylindrical metal object, such as a pipe or tube, due to its flat, nonconforming magnetically attractive side. In contrast, the present magnetic torpedo level includes a pair of laterally opposed, spaced apart ferrometallic rails extending from one side of the level, with a series of magnets imbedded in the surface of the level and contacting the two rails. The space between the rails provides clearance for the convex surface of the cylindrical ferrometallic pipe or tube to which the present level is temporarily magnetically secured.
U.S. Pat. No. 2,535,791 issued on Dec. 26, 1950 to Rothwell R. Fluke, titled “Level With Magnetic Securing Means,” describes two embodiments of magnetic levels. One embodiment includes two bar magnets extending through the thickness or height of the level, while the other embodiment includes a pair of semicircular or “horseshoe” magnets with their poles disposed to the edge of the level. Each embodiment includes a groove formed along the magnetically attractive edge, with the magnet ends conforming to the groove, in order to fit along a cylindrical object (metal pipe, tube, etc.) more closely. The Fluke level thus requires that the magnets be specially shaped to conform to such cylindrical shapes, while the present invention utilizes conventionally shaped magnets which communicate magnetically with spaced apart metal rails extending outwardly to each side thereof. Moreover, Fluke does not disclose any means of adjusting the angle of any of the level vials of his level, whereas the present level includes such angular vial adjustment for at least one level vial.
U.S. Pat. No. 2,553,668 issued on May 22, 1951 to Michael Morello, titled “Level Magnetic Attachment,” describes magnets which are removably attachable to a level by means of clips. The Morello level itself does not have any magnetic properties, whereas the present level includes permanently installed magnetic means.) As in the other levels discussed herein, Morello does not provide any means for adjusting the angle of any of the level vials of his level, unlike the present level with its at least one angularly adjustable level vial.
U.S. Pat. No. 2,695,949 issued on Nov. 30, 1954 to James H. Ashwill, titled “Illuminated Spirit Level,” describes a level having fixed horizontal, vertical, and 45 degree angle vials therein. Ashwill does not provide any means for adjusting the angle of any of the vials of his level after manufacture of the level. The bottom of the Ashwill level is provided with a magnetic plate at each end thereof, but the plates are flat on the bottom, as is the rest of the level. Ashwill does not provide any depending longitudinal rails or the like to allow his level to seat securely upon a cylindrical surface, as provided by the present magnetic torpedo level.
U.S. Pat. No. 2,789,363 issued on Apr. 23, 1957 to George E. Miley, titled “Magnetic Level,” describes two different embodiments of a level having magnetic means for temporarily securing it to a ferrous metal surface. The first embodiment includes a longitudinal groove along one surface, with a series of separate magnets mounted flush with the grooved surface and having corresponding grooves thereacross. The groove allows the Miley level to fit closely to a cylindrical surface. However, Miley does not provide any continuous ferrous metal rails to magnetically connect his magnets, as provided in the present invention. No angularly adjustable level vials are provided by Miley for either of the embodiments of his level, whereas the present magnetic torpedo level invention includes such angularly adjustable level vials.
U.S. Pat. No. 3,046,672 issued on Jul. 31, 1962 to Harry S. Lace, titled “Level,” describes a spirit level having illumination and magnetic means. The magnetic means comprises a pair of ceramic magnets which are each sandwiched between a pair of ferrometallic plates which extend slightly beyond the outer edge of the magnets, to define a channel or groove therebetween. A corresponding groove is formed along the length of the level body, to allow the level to seat on a cylindrical surface. The magnet assemblies are retractably mounted within the level body, and extend automatically due to magnetic attraction when the level is placed upon a ferrometallic surface. However, Lace does not provide continuous ferrometallic rails to defin
Fulton Christopher W.
Litman Richard C.
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